Methods for the preparation of hydroxyarenes ("phenols") have been known for a long time and are part of the "textbook knowledge" of organic chemistry. Hydroxyarenes are generally prepared by reaction of metal hydroxides with arenes containing groups which are easily nucleophilically substitutable. With this approach, problems may occur if the starting materials contain other groups which are easily attacked by a nucleophilic mechanism, such as, for example, cyano or ester groups. Undesirable side reactions are also observed in the alternatively possible synthesis by cleavage of appropriate methoxyarenes (cf. DE-A 38 35 168 and Bull. Korean Chem. Soc. 14 (1993), 717). It is an object of the present invention to provide a process which makes it possible to introduce hydroxy groups into arenes without affecting other groups which are easily attacked, such as, in particular, the cyano group.